I haven't rung up anyone yet but had a check on the websites, I found an RH m8x1 on tracy tools. 18 quid for the rotagrip HSS looks good as long as it is genuinely a 1mm pitch, 65% discount sounds a bit suspicious.
I must say the only reason I checked the pitch was because it was about a tenner for a set of 3, of a non standard pitch, and if that wasn't uncommon enough it is left hand!
The idea was to make phosphor bronze sacrificial anti backlash nuts to try and get the backlash and friction down to help with the fitting of CNC, so an investment in a tool likely to last a few sets sounds good.